This invention relates to apparatus for quantizing input groups of data samples, and to processes which such apparatus carry out.
In the prior art, various apparatus which quantize input groups of data samples have been developed to meet the need to compress the samples and thereby reduce the amount of memory which it takes to store the samples and/or reduce the transmission rate which it takes to transmit the samples. Typically, the input data samples are quantized in groups of 2 to 32 samples. Also, each data sample in the group consists of a certain number of bits such as 8 bits. Thus, as the number of data samples per group increases, and the number of bits per data sample increases, the total number of permutations of the bits in each data sample group becomes very large.
During a quantization process, several different bit permutations which are "close" to each other are all transformed to a single permutation. This single permutation constitutes one quantized group of data samples. By limiting the total number of quantized groups of data samples, the desired data compression occurs. For example, an input group of data samples which has several million bit permutations might be quantized into one of just several thousand quantized groups of data samples.
In order to quantize an input group of data samples, many operations need to be preformed by the quantizing apparatus. These operations vary in their degree of complexity with the particular process that the quantizing apparatus performs. Also, to perform the above operations, the quantizing apparatus needs to access from some type of storage module, a description or definition of all of the quantized data sample groups. This storage module varies in its storage capacity with the particular process that is being carried out.
For the quantizing process to occur quickly, the complexity of the operations that need to be performed must be low. Also, for the quantizing apparatus to be economically feasible, the size of the storage module which it uses to store the definition of all of the quantized groups of data samples must be small.
Accordingly, a primary object of the invention is to provide a novel apparatus and process for quantizing input groups of data samples which require substantially less storage capacity and/or fewer operations then the prior art.